Biasing guide for boards

ABSTRACT

A board-engaging device for saws and the like, designed to laterally urge boards toward a fence or guide during ripping and similar operations where it is necessary that each board move in a straight path for accuracy. Inclined rolls at opposite sides of the rotating tool element frictionally grip the board and hold it toward a stationary guide or fence. The rolls are vertically movable, being biased toward a work table by springs or other similar biasing devices. They can be pivoted on an attachment assembly selectively mounted to the table surface of the tool, or can be alternately mounted in a permanent fashion directly upon the table.

United States Patent 1 Schwoch et al.

[ BIASING GUIDE FOR BOARDS 21 Appl. No.: 144,727

[52] US. Cl 144/249 B, 83/418, 83/431,

83/446, 83/448, 144/242 C [51] Int. Cl B27b 5/06, B25d 7/06 [58] Field of Search 144/247, 242 R, 242 B,

144/242 D, 245 R, 253 F, 253 E, 253 R, 249, 249 B; 143/55 R, 55 A; 83/418, 431, 446, 448

[56] References Cited UNITED STATES PATENTS 1,067,360 7/1913 McSorley et a1 143/55 A [111 3,738,403 June 12, 1973 Primary ExaminerDonald R. Schran Att0'rneyWells, St. John & Roberts [57] ABSTRACT A board-engaging device for saws and the like, designed to laterally urge boards toward a fence or guide during ripping and similar operations where it is necessary that each board move in a straight path for accuracy. Inclined rolls at opposite sides of the rotating tool element frictionally grip the board and hold it toward a stationary guide or fence. The rolls are vertically movable, being biased toward a work table by springs or other similar biasing devices. They can be pivoted on an attachment assembly selectively mounted to the table surface of the tool, or can be alternately mounted in a permanent fashion directly upon the table.

5 Claims, 9 Drawing Figures PATENTEU SIEETEWZ FIG. 6

FIG. 8

FIG. 9

1 BIASING GUIDE FOR BOARDS BACKGROUND OF THE INVENTION This invention arose as a result of attempts to improve upon conventional hand guiding techniques using a table or bench saw, whether for home or for commercial use. Ripping of boards by such equipment is conventionally carried out by manually guiding each board along a stationary fence or guide. This becomes particularly difficult in the case of large boards or sheets of plywood, and typically requires two persons at opposite sides of the tool to guide the board or sheet during use of the saw. The technique involved becomes increasingly difficult as the end of the board or sheet approaches the saw, and binding of the saw blade or a misaligned edge frequently results.

To eliminate these problems and facilitate the ripping or cutting of material by table-mounted tools that use a stationary guide for the moving work piece, we have provided a device comprising one or more biased oblique rolls which engage the work piece along a plane surface, the corner engagement of each roll serving to yieldably urge the work piece toward a stationary guide or fence facing the lower peripheral surface of each roll.

While various ripping guides are on the market, they do not, to our knowledge, include oblique rolls mounted as set out herein. Angular guide rolls are shown in prior saw mill equipment, as exemplified by the prior patents to Gray, U.S. Pat. No. 550,825 and Houser, U.S. Pat No. 547,432. However, both apparently were designed for the handling of round log surfaces and both illustrate the rolls as being used to engage the round surfaces, as opposed to the present apparatus, designed to push and hold plane board surfaces adjacent to a work engaging tool.

It also has been proposed that materials being fed along a path be held against a guide by skewed rolls. Typical patents exemplifying this technique are those to Broadmeyer, U.S. Pat. No. 1,736,484, Barnes, U.S. Pat. No. 2,888,261 and Mitchell, U.S. Pat. No. 3,176,980. However the use of skewed or oblique rollers definitely prohibits reversal of the work piece, which would be urged away from the desired path if moved rearwardly to its intended direction of movement.

SUMMARY OF THE INVENTION The present apparatus is used in combination with a powered tool having a rotatable work-engaging tool element, a guide table surface and a protruding straight guide surface or fence intersecting the table surface. It comprises work-engaging means that is located above the table surface at one or more locations inwardly adjacent to the guide surface and at opposite sides of the tool element. Each work-engaging means comprises a roll that is circular in shape. Each roll is individually mounted for rotation about its axis. The mounting includes means permitting movement of the roll toward and away from the table surface. Each roll is maintained in an orientation such that its lower axis is inclined obliquely upward from the table surface, toward the guide surface. The support for the roll maintains the roll axis within a single plane perpendicular to the guide surface. Yieldable means is operatively connected to the individual supports to urge each roll toward the table surface.

One object of the present device is to eliminate the necessity of two persons guiding a work piece along a straight guide or fence. The present apparatus automatically holds down the work piece against the table surface and biases it toward the protruding guide or fence. Elimination of extra personnel for such production effort will reduce the usual cost of production.

Another object of this invention is to eliminate wasted time and material by insuring far greater accuracy in the operations carried out on each work piece along a straight guide, minimizing rejection and duplication of work.

Another object of the invention is to provide such a device requiring little or no adjustment. A properly designed device can operate on work pieces over a substantial span of dimensions without any adjustment. It is capable of adapting to variations in thickness of the work piece and can readily accommodate materials of varying width.

Another object is to provide such a deivce wherein the operator may temporarily stop the work piece while it is being worked upon and may resume movement at will. If desired, he may reverse the movement of the work piece, being assured of proper alignment thereof along a straight guide.

Another object of the invention is to provide accurate guidance of the work piece in the area immediately adjacent to a rotating power tool so as to eliminate the danger inherent in handling material close to rotating saw blades and similar devices. According to the present device, each work piece is automatically guided along the desired path and may be pushed by a rigid bar or other tool to avoid dangerous alignment of the work piece by one's hands.

These and further objects will be evident from the following disclosure, which illustrates two preferred embodiments of the invention. It is to be understood that these embodiments are merely exemplary and are not intended to exhaust the physical configurations available according to the teachings herein.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing the first embodiment of the invention as applied to a radial arm saw;

FIG. 2 is a front view of the table and guide assembly;

FIG. 3 is a top view of the assembly shown in FIG. 2;

FIG. 4 is an enlarged end view of the assembly shown in FIG. 2;

FIG. 5 is an enlarged sectional view taken along line 5-5 in FIG. 3;

FIG. 6 is a front view of a second embodiment of the invention;

FIG. 7 is a top view of the embodiment shown in FIG.

FIG. 8 is an enlarged view showing a work piece of various dimensional thickness being guided by the apparatus illustrated in FIGS. 6 and 7; and

FIG. 9 is an enlarged end view of a modification of the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1-5 illustrate a first embodiment of the invention, illustrated as an attachment suitable for use on existing table saw assemblies and similar power-operated tools. FIGS. 6-9 illustrate a second embodiment designed for mounting to the table of a saw or other equipment.

Referring now to FIG. 1, a saw unit is generally illustrated, being in the form of a radial arm saw as conventionally used for home use, as well as in commercial operations. The saw unit 10 is movably located above a work table 11, which has a planar upper surface on which the work piece is supported during operation of the equipment. A conventional longitudinal slot 12 extends along table 11 and is open to the upper surface thereof. Slot l2 conventionally receives a cross-cut guide (not shown) used in connection with the saw.

The present attachment is illustrated in FIGS. 2-5. It comprises an upright guide or fence 13 ofa length sufficient to span the saw unit 10. It may be fabricated of wood, as illustrated, or produced from suitable plastic or metal stock. Secured integrally with the guide 13 are two upright post assemblies 15 at opposite ends thereof. These post assemblies 15 movably mount the biasing rolls 22 which engage the work piece being operated upon by saw unit 10.

Each post assembly 15 is vertically slotted along its center to form transversely spaced side plates 16, which are joined by a rear post surface 17 and an upright front extension 18 that is integral with the guide 13. The post assembly 15 may be made of wood or any other suitable material. It must be rigid and of sufficient structural strength to withstand the normal forces exerted thereon during use.

The space between side plates 16 is aligned centrally with a slot 20 of upright configuration formed through the respective front extensions 18. The width of each slot 20 is equal to the interior width between side plates 16. A shaft 21 is pivoted at its upper end about a pivot shaft 24 and extends through slot 20. The diameter of shaft 21 is substantially equal to the width of the slot 20 so as to restrict movement of shaft 21 and prevent any movement of shaft 21 other than pivotal motion about the axis of pivot shaft 24. The axes of each pivot shaft 24, which are coaxial, are parallel to the line of intersection between the guide surface of fence 13 and the upper surface of table 11.

As can be seen in FIGS. 4 and 5, shaft 21 extends downwardly from pivot shaft 24 at an angular inclination relative to the horizontal. Its axis is inclined obliquely upward from the table surface toward guide 13. The vertical length of slot 20 permits sufficient pivotal movement of shaft 21 to enable roll 22 to accommodate the normal range of stock thickness which would be engaged along table 11.

A tension spring 23 extends between the lower portion of the post assembly 15 and an intermediate location along shaft 21. Roll 22 is preferably made of rubber material or similar material capable of frictionally engaging the work piece without surface damage. One or more roller units can be used in a particular installation, two being illustrated herein for guidance ofa work piece at both sides of a saw blade or other tool. The rolling engagement of the circular roll periphery urges the work piece toward the fence or guide, where it is slidably aligned parallel to its desired path of travel. The circular roll periphery might be the edge of a disk or cylindrical roll, or might have a conical or spherical configuration. The closer the roll axis approaches the vertical, the greater the lateral force on the work piece.

FIGS. 1 and 5 illustrate the manner by which a work piece is engaged by the inclined roller 22. The mounting of roller 22 is such as to maintain its center axis inclined upwardly fron table 11 toward guide 13 and within a single plane perpendicular to the inner guide surface of guide 13, so as to engage each work piece along a straight line parallel to guide 13. Because of this parallel relationship, a work piece can be moved back and forth along guide 13 without deviation of its position from the desired parallel moving path against guide 13.

For illustrative purposes, the guide device has been illustrated in FIGS. 1-5 as made of wood and adapted to be used as an attachment to a conventional radial arm saw. It is illustrated as being used for ripping a board 25. It is particularly advantageous in such an application, because it holds the individual board 25 immediately prior to engagement by the saw unit 10 and immediately after such engagement. The rollers 22 cooperate to hold the board 25 against table 1 l as well as to urge one side edge of each board against the inner surface of guide 13. The biasing force on roller 22 is sufficient to prevent undesired movement of the board 22. Furthermore, the straight line travel of each board 25 is insured throughout its path across saw unit 10. One can successfully maintain a path by simply pushing one end of board 25. This is desirable as the rear end of each board approaches saw unit 10. Instead of running the risk of using ones hands near the saw unit 10, a pushing stick or rod (not shown) can be used against the end of each board to move it through the respective rollers 22.

The present apparatus further permits effective and accurate ripping of short boards such as boards about 6 inches in length. To do this, one must place a strip of wood narrow enough to go between the saw blade and the fence under the outfeed roller 22. The incoming short board then abuts and pushes this strip as a guide member. The two abutting members act as extensions of one another to insure accurate guidance of the short board.

The second embodiment of the invention, which is illustrated in FIGS. 6-8, provides an alternate mounting arrangement in which the rollers arepermanently attached to a table member and are mounted on arcuate extended supports that protrude over a stationary upright guide.

Referring specifically to the embodiment of FIGS. 6- 8, the table member is illustrated at 31. It may be used with a saw unit such as is illustrated in FIGS. 1-5 or similar power tool machinery. It may be secured to the table 42 of such equipment in any suitable manner. A longitudinal upright guide 32 protrudes above the upper surface of table member 31. A pair of transverse arcuate arms 33 extend over guide 32. They are pivotally anchored to a table member 31 at the opposite side of guide 32 by hinges or other suitable connecting devices shown at 34. The outer end of each arm 33 rotatably carries a roller 35 about a central roller shaft 36. The shaft 36 is inclined relative to the horizontal so as to locate the axis of roller 35 at an upward incline from table 42 toward the guiding inner surface of the guide 32. The rollers 35 are yieldably biased to a lowered position. This can be attained by coiled hinge springs or by the tension springs 37 illustrated between the inner surfaces of arms 33 and table 31.

This second form of the invention operates in substantially the same manner as the first embodiment. The rollers 35 should be located at opposite sides of the power tool unit. They yieldably engage stock of varying thickness, as illustrated in FIG. 9, where a work piece is indicated by the object 40. In each instance, the upper surface of the work piece is planar and parallel to table 31. It is engaged by the outer conical corner surface along the outside of roller 35. This engagement holds the work piece against the table 42 and biases it inwardly toward guide 13.

FIG. 9 illustrates an adaptation of the second embodiment to a table saw having a stationary saw blade 41 and a movable fence 43 selectively fixed across table 44 by a clamping device 45 at each of its ends. Because the fence 43 is transversely movable the biasing rollers must also move. As shown, the previouslydescribed table section 31 is fixed to fence 43 and moves simultaneously with it across the table 42. The operation of the device is otherwise identical to the details spelled out above.

While the specific disclosure above relates to the use of cylindrical rolls or rollers as the work-engaging members, endless tracks, belts or circular disks may be substituted. in each instance, the supporting axis or axes of the work-engaging members should be inclined obliquely upward from the table toward the guide or fence surface. The line of work engagement must be tangential or parallel to the line ofintersection between the table surface and guide surface and movement of the member must be confined to a plane perpendicular to this line of intersection.

This guide device can be designed to fit and be used on any make of table saw, whether a bench saw or radial arm saw. It also is usable in conjunction with a band saw, jig saw or planer. It can be used for metalworking as well as woodworking purposes, or for cutting other solid material, as well as any other operations carried along a straight-line path. It is not our intent to limit the application of the device to any particular powered tool.

Obviously, many modifications can be made with respect to the details of this invention. For these reasons, only the following claims are intended to limit and define the scope of our invention.

Having thus described our invention, we claim:

1. In a work holder for a powered tool having a workengaging tool element, a work-supporting table surface and a guide fence:

work-engaging means at one or more locations positioned at opposite sides of the tool element, said work-engaging means each being inwardly adjacent to the guide surface, and each comprising:

a work-engaging roller member having a lower peripheral corner surface centered about an axis inclined upwardly from the work-supporting table surface toward the guide fence for rolling engagement with workpiece surfaces parallel to the table;

support means for mounting each work-engaging roller member for free rotational motion of said corner surface relative to said axis due to frictional engagement against a work piece moving across the table surface and for guidingthe roller member so as to maintain said axis within a plane perpendicular to the line of intersection between the table surface and guide fence;

and means yieldably urging each work-engaging roller member toward said table surface.

2. In a work holder for a powered tool having a workengaging tool element, a work-supporting table surface and a protruding guide fence:

work-engaging elements at one or more locations p0- sitioned at opposite sides of the tool element, said work-engaging elements being each inwardly adja cent to the guide surface, and each comprising:

a frictional work-engaging roller having an outer peripheral edge configuration movable about a support axis for rolling engagement with workpiece surfaces parallel to the table;

individual support means rotatably mounting each work-engaging roller for free movement relative to its axis;

guide means operatively connected to said individual support means for permitting movement of each work-engaging roller toward and away from the table surface in such fashion as to maintain its support axis obliquely inclined upwardly from the table surface toward the guide fence and to maintain the axis within a single plane perpendicular to the guide surface;

and yieldable means operatively connected to the individual support means for urging each workengaging roller toward the table surface.

3. An apparatus as set out in claim 2 wherein the individual support means are pivotally connected relative to the table about individual axes which are parallel to the line of intersection between the guide fence and table surface.

4. An apparatus as set out in claim 2 wherein the individual support means are pivotally connected relative to the table about individual support axes which are parallel to the line of intersection between the guide fence and table surface;

each support means being constructed so as to prevent any movement thereof other than about its respective support axis, whereby the rolling engagement of each roller on a work piece interposed between the roller and table surface will be restricted to a straight line parallel to the guide fence.

5. In a work holder for a power saw having a saw blade and an associated work-supporting table and guide fence:

a pair of yieldable work-engaging guide assemblies to the table and fence at opposite longitudinal sides of the blade for rolling engagement of workpiece surfaces parallel to the table, each guide assembly comprising:

a frictional roller having a circular peripheral edge centered about an axis inclined upwardly from the table toward the guide fence;

individual supports rotatably journalling each roller about its roller axis, said supports being mounted to the table and guide fence for permitting elevational movement of the roller relative to the work table and guide fence while maintaining the roller axis within a plane perpendicular to the line of intersection between the table and guide fence;

the lower portion of each roller edge being located across the table within the path bounded by the guide fence and the saw blade;

and yieldable means operatively connected between the individual supports and the table and guide fence for urging each roller toward the table. i 

1. In a work holder for a powered tool having a work-engaging tool element, a work-supporting table surface and a guide fence: work-engaging means at one or more locations positioned at opposite sides of the tool element, said work-engaging means each being inwardly adjacent to the guide surface, and each comprising: a work-engaging roller member having a lower peripheral corner surface centered about an axis inclined upwardly from the worksupporting table surface toward the guide fence for rolling engagement with workpiece surfaces parallel to the table; support means for mounting each work-engaging roller member for free rotational motion of said corner surface relative to said axis due to frictional engagement against a work piece moving across the table surface and for guiding the roller member so as to maintain said axis within a plane perpendicular to the line of intersection between the table surface and guide fence; and means yieldably urging each work-engaging roller member toward said table surface.
 2. In a work holder for a powered tool having a work-engaging tool element, a work-supporting table surface and a protruding guide fence: work-engaging elements at one or more locations positioned at opposite sides of the tool element, said work-engaging elements being each inwardly adjacent to the guide surface, and each comprising: a frictional work-engaging roller having an outer peripheral edge configuration movable about a support axis for rolling engagement with workpiece surfaces parallel to the table; individual support means rotatably mounting each work-engaging roller for free movement relative to its axis; guide means operatively connected to said individual support means for permitting movement of each work-engaging roller toward and away from the table surface in such fashion as to maintain its support axis obliquely inclined upwardly from the table surface toward the guide fence and to maintain the axis within a single plane perpendicular to the guide surface; and yieldable means operatively connected to the individual support means for urging each work-engaging roller toward the table surface.
 3. An apparatus as set out in claim 2 wherein the individual support means are pivotally connected relative to the table about individual axes which are parallel to the line of intersection between the guide fence and table surface.
 4. An apparatus as set out in claim 2 wherein the individual support means are pivotally connected relative to the table about individual support axes which are parallel to the line of intersection between the guide fence and table surface; each support means being constructed so as to prevent any movement thereof other than about its respective support axis, whereby the rolling engagement of each roller on a work piece interposed between the roller and table surface will be restricted to a straight line parallel to the guide fence.
 5. In a work holder for a power saw having A saw blade and an associated work-supporting table and guide fence: a pair of yieldable work-engaging guide assemblies to the table and fence at opposite longitudinal sides of the blade for rolling engagement of workpiece surfaces parallel to the table, each guide assembly comprising: a frictional roller having a circular peripheral edge centered about an axis inclined upwardly from the table toward the guide fence; individual supports rotatably journalling each roller about its roller axis, said supports being mounted to the table and guide fence for permitting elevational movement of the roller relative to the work table and guide fence while maintaining the roller axis within a plane perpendicular to the line of intersection between the table and guide fence; the lower portion of each roller edge being located across the table within the path bounded by the guide fence and the saw blade; and yieldable means operatively connected between the individual supports and the table and guide fence for urging each roller toward the table. 